Touch Sensing Period Control in OLED Displays for Lower Noise

Solution Overview

Problem

Noise is generated in organic light emitting display apparatus due to touch inputs, degrading display quality.

Innovation Solution

A display apparatus with a panel comprising sub-pixels and touch electrodes, a first driving circuit for supplying driving signals, and a second driving circuit for supplying mutual and self-sensing signals during specific periods to control the sensing period of touch inputs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If touch sensing function is continuously activated, then touch input detection capability is improved, but noise is generated that degrades display quality

Engineering Contradiction:

Improvetouch input detection capabilityVSAvoidnoise

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements periodic touch sensing by alternating between sensing periods and non-sensing periods. During sensing periods, touch electrodes are activated to detect touch inputs, while during non-sensing periods, the electrodes are deactivated to prevent noise generation. This periodic activation pattern allows the system to maintain touch detection capability while minimizing noise interference with display quality.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent segments the operation into distinct driving periods and stand-by periods. The driving period is further divided into sensing sub-periods and non-sensing sub-periods. This segmentation allows independent control of touch sensing activation, enabling the system to activate sensing only during specific segments when needed, rather than continuous activation, thereby reducing noise while maintaining touch functionality.

Inventive Principle:

Principle #1Segmentation

2Speed

If touch sensing is performed during driving period, then touch responsiveness is improved, but display quality is degraded due to noise

Engineering Contradiction:

Improvetouch responsivenessVSAvoidnoise

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent implements periodic touch sensing by alternating between sensing periods and non-sensing periods. During sensing periods, touch electrodes are activated to detect touch inputs, while during non-sensing periods, the electrodes are deactivated to prevent noise generation. This periodic activation pattern allows the system to maintain touch detection capability while minimizing noise interference with display quality.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies different operational characteristics to different time periods within the driving cycle. During specific sensing sub-periods, touch sensing is activated with high priority for responsiveness, while during other sub-periods, the system prioritizes display quality by deactivating sensing. This local differentiation of operational quality allows optimized performance for both responsiveness and display quality in their respective time windows.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If sensing period is extended, then touch detection accuracy is improved, but noise exposure time is increased

Engineering Contradiction:

Improvetouch detection accuracyVSAvoidnoise exposure time

Core Design Contradiction:

Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The patent implements periodic touch sensing by alternating between sensing periods and non-sensing periods. During sensing periods, touch electrodes are activated to detect touch inputs, while during non-sensing periods, the electrodes are deactivated to prevent noise generation. This periodic activation pattern allows the system to maintain touch detection capability while minimizing noise interference with display quality.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies partial sensing action by activating touch sensing only during specific sub-periods within the driving period rather than throughout the entire period. This partial activation provides sufficient touch detection accuracy for user interactions while significantly reducing the cumulative noise exposure time compared to continuous sensing.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12481402B2Display apparatus

Publication Date: 2025.11.25 LG DISPLAY CO LTD

AI summary

A display apparatus can include a panel which includes a plurality of sub pixels and a plurality of touch electrodes, a first driving circuit which supplies a driving signal to the panel in a driving period and holds the driving signal in the stand-by period, and a second driving circuit which supplies a mutual sensing signal to the panel and supplies a self-sensing signal to the panel in the stand-by period.